src/mesa/main/buffers.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.1
   4  *
   5  * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 /**
  27  * \file buffers.c
  28  * General framebuffer-related functions, like glClear, glScissor, etc.
  29  */
  30
  31
  32
  33 #include "glheader.h"
  34 #include "buffers.h"
  35 #include "colormac.h"
  36 #include "context.h"
  37 #include "enums.h"
  38 #include "fbobject.h"
  39 #include "state.h"
  40
  41
  42 #define BAD_MASK ~0u
  43
  44
  45 #if _HAVE_FULL_GL
  46 void GLAPIENTRY
  47 _mesa_ClearIndex( GLfloat c )
  48 {
  49    GET_CURRENT_CONTEXT(ctx);
  50    ASSERT_OUTSIDE_BEGIN_END(ctx);
  51
  52    if (ctx->Color.ClearIndex == (GLuint) c)
  53       return;
  54
  55    FLUSH_VERTICES(ctx, _NEW_COLOR);
  56    ctx->Color.ClearIndex = (GLuint) c;
  57
  58    if (!ctx->Visual.rgbMode && ctx->Driver.ClearIndex) {
  59       /* it's OK to call glClearIndex in RGBA mode but it should be a NOP */
  60       (*ctx->Driver.ClearIndex)( ctx, ctx->Color.ClearIndex );
  61    }
  62 }
  63 #endif
  64
  65
  66 /**
  67  * Specify the clear values for the color buffers.
  68  *
  69  * \param red red color component.
  70  * \param green green color component.
  71  * \param blue blue color component.
  72  * \param alpha alpha component.
  73  *
  74  * \sa glClearColor().
  75  *
  76  * Clamps the parameters and updates gl_colorbuffer_attrib::ClearColor.  On a
  77  * change, flushes the vertices and notifies the driver via the
  78  * dd_function_table::ClearColor callback.
  79  */
  80 void GLAPIENTRY
  81 _mesa_ClearColor( GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha )
  82 {
  83    GLfloat tmp[4];
  84    GET_CURRENT_CONTEXT(ctx);
  85    ASSERT_OUTSIDE_BEGIN_END(ctx);
  86
  87    tmp[0] = CLAMP(red,   0.0F, 1.0F);
  88    tmp[1] = CLAMP(green, 0.0F, 1.0F);
  89    tmp[2] = CLAMP(blue,  0.0F, 1.0F);
  90    tmp[3] = CLAMP(alpha, 0.0F, 1.0F);
  91
  92    if (TEST_EQ_4V(tmp, ctx->Color.ClearColor))
  93       return; /* no change */
  94
  95    FLUSH_VERTICES(ctx, _NEW_COLOR);
  96    COPY_4V(ctx->Color.ClearColor, tmp);
  97
  98    if (ctx->Visual.rgbMode && ctx->Driver.ClearColor) {
  99       /* it's OK to call glClearColor in CI mode but it should be a NOP */
 100       (*ctx->Driver.ClearColor)(ctx, ctx->Color.ClearColor);
 101    }
 102 }
 103
 104
 105 /**
 106  * Clear buffers.
 107  *
 108  * \param mask bit-mask indicating the buffers to be cleared.
 109  *
 110  * Flushes the vertices and verifies the parameter. If __GLcontextRec::NewState
 111  * is set then calls _mesa_update_state() to update gl_frame_buffer::_Xmin,
 112  * etc. If the rasterization mode is set to GL_RENDER then requests the driver
 113  * to clear the buffers, via the dd_function_table::Clear callback.
 114  */
 115 void GLAPIENTRY
 116 _mesa_Clear( GLbitfield mask )
 117 {
 118    GET_CURRENT_CONTEXT(ctx);
 119    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 120
 121    if (MESA_VERBOSE & VERBOSE_API)
 122       _mesa_debug(ctx, "glClear 0x%x\n", mask);
 123
 124    if (mask & ~(GL_COLOR_BUFFER_BIT |
 125                 GL_DEPTH_BUFFER_BIT |
 126                 GL_STENCIL_BUFFER_BIT |
 127                 GL_ACCUM_BUFFER_BIT)) {
 128       /* invalid bit set */
 129       _mesa_error( ctx, GL_INVALID_VALUE, "glClear(0x%x)", mask);
 130       return;
 131    }
 132
 133    if (ctx->NewState) {
 134       _mesa_update_state( ctx );        /* update _Xmin, etc */
 135    }
 136
 137    if (ctx->DrawBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 138       _mesa_error(ctx, GL_INVALID_FRAMEBUFFER_OPERATION_EXT,
 139                   "glClear(incomplete framebuffer)");
 140       return;
 141    }
 142
 143    if (ctx->DrawBuffer->Width == 0 || ctx->DrawBuffer->Height == 0)
 144       return;
 145
 146    if (ctx->RenderMode == GL_RENDER) {
 147       GLbitfield bufferMask;
 148
 149       /* don't clear depth buffer if depth writing disabled */
 150       if (!ctx->Depth.Mask)
 151          mask &= ~GL_DEPTH_BUFFER_BIT;
 152
 153       /* Build the bitmask to send to device driver's Clear function.
 154        * Note that the GL_COLOR_BUFFER_BIT flag will expand to 0, 1, 2 or 4
 155        * of the BUFFER_BIT_FRONT/BACK_LEFT/RIGHT flags, or one of the
 156        * BUFFER_BIT_COLORn flags.
 157        */
 158       bufferMask = 0;
 159       if (mask & GL_COLOR_BUFFER_BIT) {
 160          bufferMask |= ctx->DrawBuffer->_ColorDrawBufferMask[0];
 161       }
 162
 163       if ((mask & GL_DEPTH_BUFFER_BIT)
 164           && ctx->DrawBuffer->Visual.haveDepthBuffer) {
 165          bufferMask |= BUFFER_BIT_DEPTH;
 166       }
 167
 168       if ((mask & GL_STENCIL_BUFFER_BIT)
 169           && ctx->DrawBuffer->Visual.haveStencilBuffer) {
 170          bufferMask |= BUFFER_BIT_STENCIL;
 171       }
 172
 173       if ((mask & GL_ACCUM_BUFFER_BIT)
 174           && ctx->DrawBuffer->Visual.haveAccumBuffer) {
 175          bufferMask |= BUFFER_BIT_ACCUM;
 176       }
 177
 178       ASSERT(ctx->Driver.Clear);
 179       ctx->Driver.Clear(ctx, bufferMask);
 180    }
 181 }
 182
 183
 184
 185 /**
 186  * Return bitmask of BUFFER_BIT_* flags indicating which color buffers are
 187  * available to the rendering context (for drawing or reading).
 188  * This depends on the type of framebuffer.  For window system framebuffers
 189  * we look at the framebuffer's visual.  But for user-create framebuffers we
 190  * look at the number of supported color attachments.
 191  * \param fb  the framebuffer to draw to, or read from
 192  * \return  bitmask of BUFFER_BIT_* flags
 193  */
 194 static GLbitfield
 195 supported_buffer_bitmask(const GLcontext *ctx, const struct gl_framebuffer *fb)
 196 {
 197    GLbitfield mask = 0x0;
 198
 199    if (fb->Name > 0) {
 200       /* A user-created renderbuffer */
 201       GLuint i;
 202       ASSERT(ctx->Extensions.EXT_framebuffer_object);
 203       for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
 204          mask |= (BUFFER_BIT_COLOR0 << i);
 205       }
 206    }
 207    else {
 208       /* A window system framebuffer */
 209       GLint i;
 210       mask = BUFFER_BIT_FRONT_LEFT; /* always have this */
 211       if (fb->Visual.stereoMode) {
 212          mask |= BUFFER_BIT_FRONT_RIGHT;
 213          if (fb->Visual.doubleBufferMode) {
 214             mask |= BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 215          }
 216       }
 217       else if (fb->Visual.doubleBufferMode) {
 218          mask |= BUFFER_BIT_BACK_LEFT;
 219       }
 220
 221       for (i = 0; i < fb->Visual.numAuxBuffers; i++) {
 222          mask |= (BUFFER_BIT_AUX0 << i);
 223       }
 224    }
 225
 226    return mask;
 227 }
 228
 229
 230 /**
 231  * Helper routine used by glDrawBuffer and glDrawBuffersARB.
 232  * Given a GLenum naming one or more color buffers (such as
 233  * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags.
 234  */
 235 static GLbitfield
 236 draw_buffer_enum_to_bitmask(GLenum buffer)
 237 {
 238    switch (buffer) {
 239       case GL_NONE:
 240          return 0;
 241       case GL_FRONT:
 242          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_FRONT_RIGHT;
 243       case GL_BACK:
 244          return BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 245       case GL_RIGHT:
 246          return BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 247       case GL_FRONT_RIGHT:
 248          return BUFFER_BIT_FRONT_RIGHT;
 249       case GL_BACK_RIGHT:
 250          return BUFFER_BIT_BACK_RIGHT;
 251       case GL_BACK_LEFT:
 252          return BUFFER_BIT_BACK_LEFT;
 253       case GL_FRONT_AND_BACK:
 254          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT
 255               | BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 256       case GL_LEFT:
 257          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT;
 258       case GL_FRONT_LEFT:
 259          return BUFFER_BIT_FRONT_LEFT;
 260       case GL_AUX0:
 261          return BUFFER_BIT_AUX0;
 262       case GL_AUX1:
 263          return BUFFER_BIT_AUX1;
 264       case GL_AUX2:
 265          return BUFFER_BIT_AUX2;
 266       case GL_AUX3:
 267          return BUFFER_BIT_AUX3;
 268       case GL_COLOR_ATTACHMENT0_EXT:
 269          return BUFFER_BIT_COLOR0;
 270       case GL_COLOR_ATTACHMENT1_EXT:
 271          return BUFFER_BIT_COLOR1;
 272       case GL_COLOR_ATTACHMENT2_EXT:
 273          return BUFFER_BIT_COLOR2;
 274       case GL_COLOR_ATTACHMENT3_EXT:
 275          return BUFFER_BIT_COLOR3;
 276       default:
 277          /* error */
 278          return BAD_MASK;
 279    }
 280 }
 281
 282
 283 /**
 284  * Helper routine used by glReadBuffer.
 285  * Given a GLenum naming a color buffer, return the index of the corresponding
 286  * renderbuffer (a BUFFER_* value).
 287  * return -1 for an invalid buffer.
 288  */
 289 static GLint
 290 read_buffer_enum_to_index(GLenum buffer)
 291 {
 292    switch (buffer) {
 293       case GL_FRONT:
 294          return BUFFER_FRONT_LEFT;
 295       case GL_BACK:
 296          return BUFFER_BACK_LEFT;
 297       case GL_RIGHT:
 298          return BUFFER_FRONT_RIGHT;
 299       case GL_FRONT_RIGHT:
 300          return BUFFER_FRONT_RIGHT;
 301       case GL_BACK_RIGHT:
 302          return BUFFER_BACK_RIGHT;
 303       case GL_BACK_LEFT:
 304          return BUFFER_BACK_LEFT;
 305       case GL_LEFT:
 306          return BUFFER_FRONT_LEFT;
 307       case GL_FRONT_LEFT:
 308          return BUFFER_FRONT_LEFT;
 309       case GL_AUX0:
 310          return BUFFER_AUX0;
 311       case GL_AUX1:
 312          return BUFFER_AUX1;
 313       case GL_AUX2:
 314          return BUFFER_AUX2;
 315       case GL_AUX3:
 316          return BUFFER_AUX3;
 317       case GL_COLOR_ATTACHMENT0_EXT:
 318          return BUFFER_COLOR0;
 319       case GL_COLOR_ATTACHMENT1_EXT:
 320          return BUFFER_COLOR1;
 321       case GL_COLOR_ATTACHMENT2_EXT:
 322          return BUFFER_COLOR2;
 323       case GL_COLOR_ATTACHMENT3_EXT:
 324          return BUFFER_COLOR3;
 325       default:
 326          /* error */
 327          return -1;
 328    }
 329 }
 330
 331
 332 /**
 333  * Called by glDrawBuffer().
 334  * Specify which renderbuffer(s) to draw into for the first color output.
 335  * <buffer> can name zero, one, two or four renderbuffers!
 336  * \sa _mesa_DrawBuffersARB
 337  *
 338  * \param buffer  buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
 339  *
 340  * Note that the behaviour of this function depends on whether the
 341  * current ctx->DrawBuffer is a window-system framebuffer (Name=0) or
 342  * a user-created framebuffer object (Name!=0).
 343  *   In the former case, we update the per-context ctx->Color.DrawBuffer
 344  *   state var _and_ the FB's ColorDrawBuffer state.
 345  *   In the later case, we update the FB's ColorDrawBuffer state only.
 346  *
 347  * Furthermore, upon a MakeCurrent() or BindFramebuffer() call, if the
 348  * new FB is a window system FB, we need to re-update the FB's
 349  * ColorDrawBuffer state to match the context.  This is handled in
 350  * _mesa_update_framebuffer().
 351  *
 352  * See the GL_EXT_framebuffer_object spec for more info.
 353  */
 354 void GLAPIENTRY
 355 _mesa_DrawBuffer(GLenum buffer)
 356 {
 357    GLbitfield destMask;
 358    GET_CURRENT_CONTEXT(ctx);
 359    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); /* too complex... */
 360
 361    if (MESA_VERBOSE & VERBOSE_API) {
 362       _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 363    }
 364
 365    if (buffer == GL_NONE) {
 366       destMask = 0x0;
 367    }
 368    else {
 369       const GLbitfield supportedMask
 370          = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 371       destMask = draw_buffer_enum_to_bitmask(buffer);
 372       if (destMask == BAD_MASK) {
 373          /* totally bogus buffer */
 374          _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffer(buffer)");
 375          return;
 376       }
 377       destMask &= supportedMask;
 378       if (destMask == 0x0) {
 379          /* none of the named color buffers exist! */
 380          _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffer(buffer)");
 381          return;
 382       }
 383    }
 384
 385    /* if we get here, there's no error so set new state */
 386    _mesa_drawbuffers(ctx, 1, &buffer, &destMask);
 387
 388    /*
 389     * Call device driver function.
 390     */
 391    if (ctx->Driver.DrawBuffers)
 392       ctx->Driver.DrawBuffers(ctx, 1, &buffer);
 393    else if (ctx->Driver.DrawBuffer)
 394       ctx->Driver.DrawBuffer(ctx, buffer);
 395 }
 396
 397
 398 /**
 399  * Called by glDrawBuffersARB; specifies the destination color renderbuffers
 400  * for N fragment program color outputs.
 401  * \sa _mesa_DrawBuffer
 402  * \param n  number of outputs
 403  * \param buffers  array [n] of renderbuffer names.  Unlike glDrawBuffer, the
 404  *                 names cannot specify more than one buffer.  For example,
 405  *                 GL_FRONT_AND_BACK is illegal.
 406  */
 407 void GLAPIENTRY
 408 _mesa_DrawBuffersARB(GLsizei n, const GLenum *buffers)
 409 {
 410    GLint output;
 411    GLbitfield usedBufferMask, supportedMask;
 412    GLbitfield destMask[MAX_DRAW_BUFFERS];
 413    GET_CURRENT_CONTEXT(ctx);
 414    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 415
 416    if (!ctx->Extensions.ARB_draw_buffers) {
 417       _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffersARB");
 418       return;
 419    }
 420    if (n < 1 || n > (GLsizei) ctx->Const.MaxDrawBuffers) {
 421       _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)");
 422       return;
 423    }
 424
 425    supportedMask = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 426    usedBufferMask = 0x0;
 427
 428    /* complicated error checking... */
 429    for (output = 0; output < n; output++) {
 430       if (buffers[output] == GL_NONE) {
 431          destMask[output] = 0x0;
 432       }
 433       else {
 434          destMask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 435          if (destMask[output] == BAD_MASK
 436              || _mesa_bitcount(destMask[output]) > 1) {
 437             _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)");
 438             return;
 439          }
 440          destMask[output] &= supportedMask;
 441          if (destMask[output] == 0) {
 442             _mesa_error(ctx, GL_INVALID_OPERATION,
 443                         "glDrawBuffersARB(unsupported buffer)");
 444             return;
 445          }
 446          if (destMask[output] & usedBufferMask) {
 447             /* can't specify a dest buffer more than once! */
 448             _mesa_error(ctx, GL_INVALID_OPERATION,
 449                         "glDrawBuffersARB(duplicated buffer)");
 450             return;
 451          }
 452
 453          /* update bitmask */
 454          usedBufferMask |= destMask[output];
 455       }
 456    }
 457
 458    /* OK, if we get here, there were no errors so set the new state */
 459    _mesa_drawbuffers(ctx, n, buffers, destMask);
 460
 461    /*
 462     * Call device driver function.
 463     */
 464    if (ctx->Driver.DrawBuffers)
 465       ctx->Driver.DrawBuffers(ctx, n, buffers);
 466    else if (ctx->Driver.DrawBuffer)
 467       ctx->Driver.DrawBuffer(ctx, buffers[0]);
 468 }
 469
 470
 471 /**
 472  * Set color output state.  Traditionally, there was only one color
 473  * output, but fragment programs can now have several distinct color
 474  * outputs (see GL_ARB_draw_buffers).  This function sets the state
 475  * for one such color output.
 476  * \param ctx  current context
 477  * \param output  which fragment program output
 478  * \param buffer  buffer to write to (like GL_LEFT)
 479  * \param destMask  BUFFER_* bitmask
 480  *                  (like BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 481  */
 482 static void
 483 set_color_output(GLcontext *ctx, GLuint output, GLenum buffer,
 484                  GLbitfield destMask)
 485 {
 486    struct gl_framebuffer *fb = ctx->DrawBuffer;
 487
 488    ASSERT(output < ctx->Const.MaxDrawBuffers);
 489
 490    /* Set per-FBO state */
 491    fb->ColorDrawBuffer[output] = buffer;
 492    fb->_ColorDrawBufferMask[output] = destMask;
 493    /* not really needed, will be set later */
 494    fb->_NumColorDrawBuffers[output] = 0;
 495
 496    if (fb->Name == 0) {
 497       /* Only set the per-context DrawBuffer state if we're currently
 498        * drawing to a window system framebuffer.
 499        */
 500       ctx->Color.DrawBuffer[output] = buffer;
 501    }
 502 }
 503
 504
 505 /**
 506  * Helper function to set the GL_DRAW_BUFFER state in the context and
 507  * current FBO.
 508  *
 509  * All error checking will have been done prior to calling this function
 510  * so nothing should go wrong at this point.
 511  *
 512  * \param ctx  current context
 513  * \param n    number of color outputs to set
 514  * \param buffers  array[n] of colorbuffer names, like GL_LEFT.
 515  * \param destMask  array[n] of BUFFER_* bitmasks which correspond to the
 516  *                  colorbuffer names.  (i.e. GL_FRONT_AND_BACK =>
 517  *                  BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 518  */
 519 void
 520 _mesa_drawbuffers(GLcontext *ctx, GLuint n, const GLenum *buffers,
 521                   const GLbitfield *destMask)
 522 {
 523    GLbitfield mask[MAX_DRAW_BUFFERS];
 524    GLuint output;
 525
 526    if (!destMask) {
 527       /* compute destMask values now */
 528       const GLbitfield supportedMask
 529          = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 530       for (output = 0; output < n; output++) {
 531          mask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 532          ASSERT(mask[output] != BAD_MASK);
 533          mask[output] &= supportedMask;
 534       }
 535       destMask = mask;
 536    }
 537
 538    for (output = 0; output < n; output++) {
 539       set_color_output(ctx, output, buffers[output], destMask[output]);
 540    }
 541
 542    /* set remaining color outputs to NONE */
 543    for (output = n; output < ctx->Const.MaxDrawBuffers; output++) {
 544       set_color_output(ctx, output, GL_NONE, 0x0);
 545    }
 546
 547    ctx->NewState |= _NEW_COLOR;
 548 }
 549
 550
 551 /**
 552  * Like \sa _mesa_drawbuffers(), this is a helper function for setting
 553  * GL_READ_BUFFER state in the context and current FBO.
 554  * \param ctx  the rendering context
 555  * \param buffer  GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc.
 556  * \param bufferIndex  the numerical index corresponding to 'buffer'
 557  */
 558 void
 559 _mesa_readbuffer(GLcontext *ctx, GLenum buffer, GLint bufferIndex)
 560 {
 561    struct gl_framebuffer *fb = ctx->ReadBuffer;
 562
 563    if (fb->Name == 0) {
 564       /* Only update the per-context READ_BUFFER state if we're bound to
 565        * a window-system framebuffer.
 566        */
 567       ctx->Pixel.ReadBuffer = buffer;
 568    }
 569
 570    fb->ColorReadBuffer = buffer;
 571    fb->_ColorReadBufferIndex = bufferIndex;
 572
 573    ctx->NewState |= _NEW_PIXEL;
 574 }
 575
 576
 577
 578 /**
 579  * Called by glReadBuffer to set the source renderbuffer for reading pixels.
 580  * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
 581  */
 582 void GLAPIENTRY
 583 _mesa_ReadBuffer(GLenum buffer)
 584 {
 585    struct gl_framebuffer *fb;
 586    GLbitfield supportedMask;
 587    GLint srcBuffer;
 588    GET_CURRENT_CONTEXT(ctx);
 589    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 590
 591    if (MESA_VERBOSE & VERBOSE_API)
 592       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 593
 594    fb = ctx->ReadBuffer;
 595
 596    if (MESA_VERBOSE & VERBOSE_API)
 597       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 598
 599    if (fb->Name > 0 && buffer == GL_NONE) {
 600       /* This is legal for user-created framebuffer objects */
 601       srcBuffer = -1;
 602    }
 603    else {
 604       /* general case / window-system framebuffer */
 605       srcBuffer = read_buffer_enum_to_index(buffer);
 606       if (srcBuffer == -1) {
 607          _mesa_error(ctx, GL_INVALID_ENUM,
 608                      "glReadBuffer(buffer=0x%x)", buffer);
 609          return;
 610       }
 611       supportedMask = supported_buffer_bitmask(ctx, fb);
 612       if (((1 << srcBuffer) & supportedMask) == 0) {
 613          _mesa_error(ctx, GL_INVALID_OPERATION,
 614                      "glReadBuffer(buffer=0x%x)", buffer);
 615          return;
 616       }
 617    }
 618
 619    /* OK, all error checking has been completed now */
 620
 621    _mesa_readbuffer(ctx, buffer, srcBuffer);
 622
 623    /*
 624     * Call device driver function.
 625     */
 626    if (ctx->Driver.ReadBuffer)
 627       (*ctx->Driver.ReadBuffer)(ctx, buffer);
 628 }
 629
 630
 631 #if _HAVE_FULL_GL
 632
 633 /**
 634  * XXX THIS IS OBSOLETE - drivers should take care of detecting window
 635  * size changes and act accordingly, likely calling _mesa_resize_framebuffer().
 636  *
 637  * GL_MESA_resize_buffers extension.
 638  *
 639  * When this function is called, we'll ask the window system how large
 640  * the current window is.  If it's a new size, we'll call the driver's
 641  * ResizeBuffers function.  The driver will then resize its color buffers
 642  * as needed, and maybe call the swrast's routine for reallocating
 643  * swrast-managed depth/stencil/accum/etc buffers.
 644  * \note This function should only be called through the GL API, not
 645  * from device drivers (as was done in the past).
 646  */
 647
 648 void _mesa_resizebuffers( GLcontext *ctx )
 649 {
 650    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 651
 652    if (MESA_VERBOSE & VERBOSE_API)
 653       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 654
 655    if (!ctx->Driver.GetBufferSize) {
 656       return;
 657    }
 658
 659    if (ctx->WinSysDrawBuffer) {
 660       GLuint newWidth, newHeight;
 661       GLframebuffer *buffer = ctx->WinSysDrawBuffer;
 662
 663       assert(buffer->Name == 0);
 664
 665       /* ask device driver for size of output buffer */
 666       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 667
 668       /* see if size of device driver's color buffer (window) has changed */
 669       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 670          if (ctx->Driver.ResizeBuffers)
 671             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 672       }
 673    }
 674
 675    if (ctx->WinSysReadBuffer
 676        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 677       GLuint newWidth, newHeight;
 678       GLframebuffer *buffer = ctx->WinSysReadBuffer;
 679
 680       assert(buffer->Name == 0);
 681
 682       /* ask device driver for size of read buffer */
 683       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 684
 685       /* see if size of device driver's color buffer (window) has changed */
 686       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 687          if (ctx->Driver.ResizeBuffers)
 688             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 689       }
 690    }
 691
 692    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 693 }
 694
 695
 696 /*
 697  * XXX THIS IS OBSOLETE
 698  */
 699 void GLAPIENTRY
 700 _mesa_ResizeBuffersMESA( void )
 701 {
 702    GET_CURRENT_CONTEXT(ctx);
 703
 704    if (ctx->Extensions.MESA_resize_buffers)
 705       _mesa_resizebuffers( ctx );
 706 }
 707
 708
 709 /*
 710  * XXX move somewhere else someday?
 711  */
 712 void GLAPIENTRY
 713 _mesa_SampleCoverageARB(GLclampf value, GLboolean invert)
 714 {
 715    GET_CURRENT_CONTEXT(ctx);
 716
 717    if (!ctx->Extensions.ARB_multisample) {
 718       _mesa_error(ctx, GL_INVALID_OPERATION, "glSampleCoverageARB");
 719       return;
 720    }
 721
 722    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 723    ctx->Multisample.SampleCoverageValue = (GLfloat) CLAMP(value, 0.0, 1.0);
 724    ctx->Multisample.SampleCoverageInvert = invert;
 725    ctx->NewState |= _NEW_MULTISAMPLE;
 726 }
 727
 728 #endif /* _HAVE_FULL_GL */
 729
 730
 731
 732 /**
 733  * Define the scissor box.
 734  *
 735  * \param x, y coordinates of the scissor box lower-left corner.
 736  * \param width width of the scissor box.
 737  * \param height height of the scissor box.
 738  *
 739  * \sa glScissor().
 740  *
 741  * Verifies the parameters and updates __GLcontextRec::Scissor. On a
 742  * change flushes the vertices and notifies the driver via
 743  * the dd_function_table::Scissor callback.
 744  */
 745 void
 746 _mesa_set_scissor(GLcontext *ctx,
 747                   GLint x, GLint y, GLsizei width, GLsizei height)
 748 {
 749    if (x == ctx->Scissor.X &&
 750        y == ctx->Scissor.Y &&
 751        width == ctx->Scissor.Width &&
 752        height == ctx->Scissor.Height)
 753       return;
 754
 755    FLUSH_VERTICES(ctx, _NEW_SCISSOR);
 756    ctx->Scissor.X = x;
 757    ctx->Scissor.Y = y;
 758    ctx->Scissor.Width = width;
 759    ctx->Scissor.Height = height;
 760
 761    if (ctx->Driver.Scissor)
 762       ctx->Driver.Scissor( ctx, x, y, width, height );
 763 }
 764
 765
 766 void GLAPIENTRY
 767 _mesa_Scissor( GLint x, GLint y, GLsizei width, GLsizei height )
 768 {
 769    GET_CURRENT_CONTEXT(ctx);
 770    ASSERT_OUTSIDE_BEGIN_END(ctx);
 771
 772    if (width < 0 || height < 0) {
 773       _mesa_error( ctx, GL_INVALID_VALUE, "glScissor" );
 774       return;
 775    }
 776
 777    if (MESA_VERBOSE & VERBOSE_API)
 778       _mesa_debug(ctx, "glScissor %d %d %d %d\n", x, y, width, height);
 779
 780    _mesa_set_scissor(ctx, x, y, width, height);
 781 }
 782
 783
 784
 785 /**********************************************************************/
 786 /** \name Initialization */
 787 /*@{*/
 788
 789 /**
 790  * Initialize the context's scissor state.
 791  * \param ctx  the GL context.
 792  */
 793 void
 794 _mesa_init_scissor(GLcontext *ctx)
 795 {
 796    /* Scissor group */
 797    ctx->Scissor.Enabled = GL_FALSE;
 798    ctx->Scissor.X = 0;
 799    ctx->Scissor.Y = 0;
 800    ctx->Scissor.Width = 0;
 801    ctx->Scissor.Height = 0;
 802 }
 803
 804
 805 /**
 806  * Initialize the context's multisample state.
 807  * \param ctx  the GL context.
 808  */
 809 void
 810 _mesa_init_multisample(GLcontext *ctx)
 811 {
 812    ctx->Multisample.Enabled = GL_FALSE;
 813    ctx->Multisample.SampleAlphaToCoverage = GL_FALSE;
 814    ctx->Multisample.SampleAlphaToOne = GL_FALSE;
 815    ctx->Multisample.SampleCoverage = GL_FALSE;
 816    ctx->Multisample.SampleCoverageValue = 1.0;
 817    ctx->Multisample.SampleCoverageInvert = GL_FALSE;
 818 }
 819
 820 /*@}*/